1. Field of the Invention
The present invention relates to a giga-bit interface converters (GBICs), and particularly to GBICs having shielding doors to protect a user""s eyes from harm when a mating plug is withdrawn from the GBIC.
2. Description of Related Art
GBICs are widely used for bidirectional transmission of data between an electrical interface and an optical data link. A GBIC receives electrically encoded data signals, converts them into optical signals, and transmits the optical signals over the optical data link. The GBIC also receives optically encoded data signals, converts them into electrical signals, and transmits the electrical signals onto the electrical interface.
Transmission and receipt of optically encoded data signals are typically performed by a laser diode and a photo diode encased within the GBIC. Photo signals emitted from the laser diode are harmful to human eyes. Therefore, a typical GBIC has a shielding door to protect a user""s eyes when a mating plug is withdrawn from the GBIC.
Presently, two kinds of shielding door configurations are commonplace. In the first configuration, the shielding door returns to a closed position with the aid of a spring. In the second configuration, the shielding door returns to a closed position due to the resilient nature of the door itself.
U.S. Pat. No. 5,879,173 discloses a GBIC with a shielding door having the abovementioned first configuration. A spring such as a torsion spring is mounted on a pivotable post of the shielding door. The spring resiliently returns the shielding door to a closed position parallel to a front face of a receptacle of the GBIC. Unfortunately, the spring is prone to fall out of position, particularly after repeated opening and closing of the shielding door.
A GBIC with a shielding door having the abovementioned second configuration solves the above problem of the first configuration. The GBIC comprises a base having a bottom plate, and two side walls extending upwardly from the bottom plate. A revertible shielding door is pivotably positioned in a front face of the base, and remains perpendicular to the bottom plate. A spring arm extends from one end of the shielding door, and is fixed to an intermediate portion of the base. When the shielding door is pivoted to be parallel to the bottom plate, the spring arm is resiliently deformed. The spring arm can therefore resiliently return the shielding door to its original position.
In the above-described second configuration of the shielding door, the spring arm is a part of the shielding door. This makes the structure of the shielding door unduly complicated. Furthermore, the spring arm is prone to break at a point where it interconnects with the shielding door, particularly after it has become fatigued from repeated use. The shielding door is thus easily damaged, and needs frequent replacement.
In view of the above-described drawbacks of the related art, an object of the present invention is to provide a GBIC having a durable shielding door.
A further object of the present invention is to provide a GBIC having a shielding door with a the spring that reliably remains in correct position even after repeated use.
In order to achieve the objects set above, a GBIC in accordance with the present invention comprises a base having a bottom plate and two side walls extending upwardly from the bottom plate. A revertible shielding door is pivotably positioned in a front of the base, and remains perpendicular to the bottom plate. A post is formed on a rear side of the shielding door, and a block is formed on the base. A spring beam has an arcuate front end and a rear end. The rear end is fixed on the block, and the front end sits on the post of the shielding door. When a complementary plug connector is inserted into the GBIC, the front end of the spring beam is deformably pushed upwardly by the post. A spring force is thereby generated in the spring beam, which exerts a downward force on the post. When the plug connector is withdrawn from the GBIC, the spring force of the spring beam pushes the post down. This causes the shielding door to rotatingly return to its original position.